Doujin Issei serves in the Experts of Justice, an international police force dedicated to countering the BF Group's global threat. He frequently partners with Youshi during operations. As a warrior-monk, he harnesses Taoist magic through paper talismans to manifest diverse supernatural effects. His combat expertise centers on obfuscation, leveraging illusions and voluntary shapeshifting to disorient and incapacitate adversaries. Equipped with enchanted items, he entraps enemies in layered illusions, heightening his effectiveness in creating tactical confusion. His role anchors him in the broader struggle against forces pursuing worldwide domination, where his capabilities bolster the Experts of Justice's operational strategies.